(eta(6)-[7]Heliphene)tricarbonylchromium via an Optimized Preparation of [7]Heliphene

Optimized procedures to [7]heliphene are described that allowed the synthesis of ((6)-[7]heliphene)tricarbonylchromium and a preliminary exploration of its chemical behavior. DFT calculations provide structural and energetic information on this complex and its haptomeric isomers. Attempts to prepare the corresponding ([7]heliphene)chromium sandwich failed so far, but DFT evidence is presented to indicate that the target should be accessible.This work was supported by the NSF (CHE 0907800). We thank Professor Charles B. Harris for the use of the calculation resources from the National Energy Research Scientific Computing Center, backed by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. S.C.N. acknowledges the award of a Vietnam International Education Development (VIED) graduate research fellowship. We are grateful for additional experimental contributions from D. Ryan Anderson, Thomas Carl, Hiufung Chu, Rainer Diercks, Sangdon Han, Alex Fai Lee, Florian Montermini, and Moonsub Shim